Over lunch a week ago, Paul Wolfowitz mentioned that he had been reading a 1930 essay by Winston Churchill speculating on what might have happened if Robert E. Lee had won the Battle of Gettysburg. The defeated Union might have sued for peace, Churchill's essay argued, the American continent might have been divided, and Britain might have gained leverage.

Now, that's interesting: On the eve of a possible war with Iraq, the deputy secretary of defense is pondering one of military history's "what ifs."

Wolfowitz lists some of the other books on his reading table these days, and they highlight what must be going through his mind as he tries to think through the Iraq issue. He mentions that he's reading a collection of essays called "Taking Back Islam: American Muslims Reclaim Their Faith." He explains: "We need an Islamic reformation, and I think there is real hope for one." For Wolfowitz, that hope for a postwar transformation of the Muslim world is clearly a powerful intellectual rationale for a change of regime in Baghdad.

Wolfowitz also notes that he has been reading "Supreme Command" by Eliot A. Cohen, a study of four great wartime heads of state: Abraham Lincoln, Georges Clemenceau, Churchill and David Ben-Gurion.

What's interesting about this book, in terms of Iraq policy, is that it challenges the conventional wisdom that military strategy should be left to the generals (many of whom, at present, appear to be wary about a U.S. invasion of Iraq). Cohen argues that civilians often have the leadership gifts to command their nation's forces more decisively than the military (or former generals who are running the State Department).

What runs through all these books is that they highlight, in different ways, the stakes for the Bush administration as it contemplates a final decision on Iraq. An invasion may be the right choice, but anyone who pretends it's an easy one hasn't thought it through.

Iraq is a close call because the risks are so evenly distributed. It could be a great success that opens a glorious new chapter in the history of the Arab world, as I have long hoped. Or it could be a frustrating killing ground that would embolden America's adversaries and endanger the United States and its allies, as many critics have warned.

Either way, Iraq is a roll of the dice. It's a war of choice -- not one that would be imposed on the United States. You can argue that war against Iraq might be self-defense down the road, but so far there's little evidence of that "smoking gun." So it's not surprising that as the date for an invasion approaches, America's allies are becoming a little wobbly. Intelligence sources predict that the testimony of the Iraqi scientist who was questioned yesterday by U.N. inspectors in Baghdad will stiffen resolve.

Clearly, Wolfowitz looks at Iraq from the perspective of his earlier work as a nuclear strategist. That intellectual heritage -- grounded in the lessons of Munich -- tells him that it is better to fight little wars early than to fight big wars later.

I cannot be sure whether Wolfowitz also embraces what I view as two critical requirements for U.S. success in Iraq. The first is that it be the Iraqis' war of liberation, rather than an American-Israeli diktat; the second is that it be accompanied by aggressive American efforts to make peace between Israel and the Palestinians.

What's clear is that Wolfowitz is thinking about both issues. We discussed the possibility that the liberation of Iraq might be like the liberation of France in 1944 -- in that, although the indigenous Resistance played only a minimal role in driving out the enemy, this mythic movement proved crucial in rebuilding the country later. "France is closer to the right analogy" than postwar Japan, Wolfowitz said.

"The Arab world needs a sense of confidence and achievement," he said. An Iraqi invasion wouldn't accomplish that, he conceded, but he added: "I'm talking about two decades of change."

On the prospects for Arab-Israeli peace, it's hard to be sanguine when the Bush administration is allowing Israeli Prime Minister Ariel Sharon to block Palestinians from even attending a peace conference in London this week.

But Wolfowitz doesn't come across as the one-dimensional, pro-Israeli figure sometimes depicted. He notes that "the Israelis have to be kept out" of any U.S.-led invasion of Iraq, and he says that in the postwar environment, "our stake in pushing for a Palestinian state will grow." He explains that he favors concrete measures, such as dealing with Israeli settlements, rather than focusing on diplomatic "process" issues.

Wolfowitz says that his most important concern, if war comes, will be to prevent the Iraqis from using weapons of mass destruction against invading U.S. forces or neighboring states.

That's the hardest nut for me to crack -- the risk that a war fought to preempt weapons of mass destruction could trigger the use of those very weapons. The CIA director, George Tenet, has warned of this danger. President Bush and his advisers shouldn't feel embarrassed if they want to think this conundrum through very carefully before taking final action.